In a perfect world, 99.9% of AIX administrators would prefer their systems to look like this:

# lspv | grep rootvg

hdisk000c342c68dfcbdfbrootvgactive

However, in reality, 99.9% of AIX administrators live with systems that look something like this:

# lspv | grep rootvg

hdisk3900c342c68dfcbdfbrootvgactive

And 99.9% of them don’t have time to tidy up their systems so that rootvg resides on hdisk0.

Most of them have much bigger fish to fry, such as performance, virtualisation, automation, security, project delivery, TPS reports, etc!

If they did have time, they could use the mirrorvg and rendev commands to ‘bring order to the Universe’.

WARNING! Let me make this perfectly clear! The procedure that is shown below is NOT SUPPORTED by IBM. If you choose to follow these procedures, DO NOT contact IBM support for help. They will not be able to assist you. YOU HAVE BEEN WARNED!

Note: Disk drive devices that are members of the root volume group, or that will become members of the root volume group (by means of LVM or install procedures), must not be renamed. Renaming such disk drives may interfere with the ability to recover from certain scenarios, including boot failures. Some devices may have special requirements on their names in order for other devices or applications to use them. Using the rendev command to rename such a device may result in the device being unusable.

Note: To protect the configuration database, the rendev command cannot be interrupted once it has started. Trying to stop this command before completion, could result in
a corrupted database.

In a previous post
I discussed how you can identify some of the different types of a PowerVM Capacity
on Demand (CoD) activation keys from IBM.

Recently I had to Activate Memory Expansion (AME) on a
couple of POWER7 systems. I discovered that all of the keys contained a similar
string. It appears that if a CoD key contains the string CA1F0000000800then it is safe to assume it will activate
AME for a particular system. e.g.

9741EF3AE6969F17CA1F0000000800419D

937A1240F00F5B05CA1F0000000800413D

And while I’m talking about AME, I thought I’d share this
tip as well.

I was performing a demo of AME for my team and wanted to
change the AME expansion factor using DLPAR during the demo. I did not want to
use the HMC GUI but rather the HMC command line (as it’s faster).

To change the expansion factor for an LPAR (that’s enabled
for AME), you can use the chhwres
command from the HMC CLI.

During the demo I highlighted the current (running)
expansion factor for the LPAR (using the lshwres
command).